POV-Ray : Newsgroups : povray.binaries.images : Granite_21 - the final macro Server Time
26 Sep 2022 02:33:16 EDT (-0400)
  Granite_21 - the final macro (Message 9 to 18 of 30)  
<<< Previous 8 Messages Goto Latest 10 Messages Next 10 Messages >>>
From: Samuel B 
Subject: Re: Granite_21 - the final macro
Date: 13 Sep 2021 19:15:00
Message: <web.613fdb40b21f010ccb705ca46e741498@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 10-9-2021 om 22:36 schreef Samuel B.:
> > Oh, that reminds me. I know your specialty is more on the geological side of
> > things, but a great tool has just become available for free: KrystalShaper (
> > http://www.jcrystal.com/products/krystalshaper/ ) It provides a catalog of
> > hundreds of minerals, plus tools to analyze and export geometry. Might be worth
> > checking out.
> >
> Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
> my cup of tea... ;-)

I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
me convert HKL values to planes...

> The output could be the basis for crystal renders of quality. Not much
> time at the moment, but I keep in mind.

What's your camera aspect there? The crystal looks stretched vertically.

It is a cool program, I just wish I could figure out my HKL issues so I can do
more with it. (My previous searches didn't turn up much useful info, or maybe I
wasn't comprehending what I saw...)

Sam


Post a reply to this message

From: Thomas de Groot
Subject: Re: Granite_21 - the final macro
Date: 14 Sep 2021 02:54:50
Message: <6140473a$1@news.povray.org>
Op 14/09/2021 om 01:14 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 10-9-2021 om 22:36 schreef Samuel B.:
>>> Oh, that reminds me. I know your specialty is more on the geological side of
>>> things, but a great tool has just become available for free: KrystalShaper (
>>> http://www.jcrystal.com/products/krystalshaper/ ) It provides a catalog of
>>> hundreds of minerals, plus tools to analyze and export geometry. Might be worth
>>> checking out.
>>>
>> Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
>> my cup of tea... ;-)
> 
> I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
> some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
> me convert HKL values to planes...
> 
That is correct. It is/was used in crystallography for mapping mineral 
indices and do all sort of exciting things, calculating angles and 
intersections. Only, as a freshman, I was not particularly interested in 
this branch of geology! Hammering away at overturned, anticlinal rock 
sections: /That/ was what life was about! ;-)

But seriously, I do not remember how it worked exactly but it certainly 
could be of help to you I guess. I still have a Wulff net somewhere 
here, gathering dust.

>> The output could be the basis for crystal renders of quality. Not much
>> time at the moment, but I keep in mind.
> 
> What's your camera aspect there? The crystal looks stretched vertically.
> 
For the demo image I didn't bother with the scene details; just used the 
standard scene code provided by the app.

> It is a cool program, I just wish I could figure out my HKL issues so I can do
> more with it. (My previous searches didn't turn up much useful info, or maybe I
> wasn't comprehending what I saw...)
> 
I know what you mean. These are a couple sites which explain the use of 
the Wulff net. There are more of course, but these are fairly basic.

http://www.minsocam.org/ammin/AM25/AM25_689.pdf
https://www.doitpoms.ac.uk/tlplib/stereographic/wulff_construct.php

However, to tell the truth, I remain a bit baffled when I see those 
things again, after all those years. I am not really sure I understand; 
I think you are more familiar with all this.

-- 
Thomas


Post a reply to this message

From: Samuel B 
Subject: Re: Granite_21 - the final macro
Date: 15 Sep 2021 19:25:00
Message: <web.6142808fb21f010ccb705ca46e741498@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> (...)
> Only, as a freshman, I was not particularly interested in
> this branch of geology! Hammering away at overturned, anticlinal rock
> sections: /That/ was what life was about! ;-)

Yeah, being out in the field is wonderful. I know our reasons for being out
there were for different reasons, but I also know the thrill of finding
something interesting and tracking it down. I really miss it.

> Op 14/09/2021 om 01:14 schreef Samuel B.:
> > It is a cool program, I just wish I could figure out my HKL issues so I can do
> > more with it. (My previous searches didn't turn up much useful info, or maybe I
> > wasn't comprehending what I saw...)
> >
> I know what you mean. These are a couple sites which explain the use of
> the Wulff net. There are more of course, but these are fairly basic.
>
> http://www.minsocam.org/ammin/AM25/AM25_689.pdf
> https://www.doitpoms.ac.uk/tlplib/stereographic/wulff_construct.php
>
> However, to tell the truth, I remain a bit baffled when I see those
> things again, after all those years. I am not really sure I understand;
> I think you are more familiar with all this.

No, I don't think I'm any more familiar with these things than you are...
probably less so. Thanks for the links. But I looked at them and to be honest,
the information looks very thick. So thick I'm not actually sure if it would be
any help in my endeavors...


Sam


Post a reply to this message

From: Thomas de Groot
Subject: Re: Granite_21 - the final macro
Date: 16 Sep 2021 02:45:55
Message: <6142e823$1@news.povray.org>
Op 16/09/2021 om 01:23 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> (...)
>> Only, as a freshman, I was not particularly interested in
>> this branch of geology! Hammering away at overturned, anticlinal rock
>> sections: /That/ was what life was about! ;-)
> 
> Yeah, being out in the field is wonderful. I know our reasons for being out
> there were for different reasons, but I also know the thrill of finding
> something interesting and tracking it down. I really miss it.
> 
I can understand that.

>> Op 14/09/2021 om 01:14 schreef Samuel B.:
>>> It is a cool program, I just wish I could figure out my HKL issues so I can do
>>> more with it. (My previous searches didn't turn up much useful info, or maybe I
>>> wasn't comprehending what I saw...)
>>>
>> I know what you mean. These are a couple sites which explain the use of
>> the Wulff net. There are more of course, but these are fairly basic.
>>
>> http://www.minsocam.org/ammin/AM25/AM25_689.pdf
>> https://www.doitpoms.ac.uk/tlplib/stereographic/wulff_construct.php
>>
>> However, to tell the truth, I remain a bit baffled when I see those
>> things again, after all those years. I am not really sure I understand;
>> I think you are more familiar with all this.
> 
> No, I don't think I'm any more familiar with these things than you are...
> probably less so. Thanks for the links. But I looked at them and to be honest,
> the information looks very thick. So thick I'm not actually sure if it would be
> any help in my endeavors...
> 
Yeah... I know what you mean. One of the reasons I didn't get very far 
in crystallography. I have some 3D visualisation skills :-) but these 
kind of exercises always left me profoundly baffled I confess. Otoh, I 
believe they /may/ unlock certain geometrical symmetry problems proper 
to certain mineral classes.

-- 
Thomas


Post a reply to this message

From: Bald Eagle
Subject: Re: Granite_21 - the final macro
Date: 16 Sep 2021 06:30:00
Message: <web.61431c5fb21f010c1f9dae3025979125@news.povray.org>
"Samuel B." <stb### [at] hotmailcom> wrote:

> > Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
> > my cup of tea... ;-)
>
> I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
> some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
> me convert HKL values to planes...
>

> It is a cool program, I just wish I could figure out my HKL issues so I can do
> more with it. (My previous searches didn't turn up much useful info, or maybe I
> wasn't comprehending what I saw...)


Aren't the HKL values just the vector normals of the planes?
That's what the wikipedia articles suggested on my brief skim.

Would not plane {y, 0} have an hkl index of <0,1,0>?

Not sure what the overall goal is, so not sure what to suggest to test this.

- Bill


Post a reply to this message

From: Thomas de Groot
Subject: Re: Granite_21 - the final macro
Date: 16 Sep 2021 07:48:48
Message: <61432f20$1@news.povray.org>
Op 16-9-2021 om 12:28 schreef Bald Eagle:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> 
>>> Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
>>> my cup of tea... ;-)
>>
>> I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
>> some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
>> me convert HKL values to planes...
>>
> 
>> It is a cool program, I just wish I could figure out my HKL issues so I can do
>> more with it. (My previous searches didn't turn up much useful info, or maybe I
>> wasn't comprehending what I saw...)
> 
> 
> Aren't the HKL values just the vector normals of the planes?
> That's what the wikipedia articles suggested on my brief skim.
> 
> Would not plane {y, 0} have an hkl index of <0,1,0>?
> 
> Not sure what the overall goal is, so not sure what to suggest to test this.
> 
If I remember correctly, that is indeed the case I believe.

-- 
Thomas


Post a reply to this message

From: Bald Eagle
Subject: Re: Granite_21 - the final macro
Date: 16 Sep 2021 13:30:00
Message: <web.61437e38b21f010c1f9dae3025979125@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:

> > Aren't the HKL values just the vector normals of the planes?
> > That's what the wikipedia articles suggested on my brief skim.
> >
> > Would not plane {y, 0} have an hkl index of <0,1,0>?
> >
> > Not sure what the overall goal is, so not sure what to suggest to test this.
> >
> If I remember correctly, that is indeed the case I believe.
>
> --
> Thomas

So then, to some degree, the unit cell for the crystal should be some form of
intersection between all of the planes that the hkl indices define. (?)  Does
the file format include any data that would serve as an offset?

Creating the most basic crystal shapes, probably starting with cubic NaCl, might
give a clue as to how to code an implementation of that notational system.


Post a reply to this message

From: Samuel B 
Subject: Re: Granite_21 - the final macro
Date: 16 Sep 2021 19:00:00
Message: <web.6143cc4fb21f010ccb705ca46e741498@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> Aren't the HKL values just the vector normals of the planes?
> That's what the wikipedia articles suggested on my brief skim.
>
> Would not plane {y, 0} have an hkl index of <0,1,0>?

That's probably the case with simple cubic crystal systems. Other systems, like
hexagonal, monoclinic, etc., are a bit different. I should try to get a cubic
system to work first.

> Not sure what the overall goal is, so not sure what to suggest to test this.

My goal is to simply convert HKL values to normal vectors, and then to build
crystals from those using intersecting planes.

Sam


Post a reply to this message

From: Samuel B 
Subject: Re: Granite_21 - the final macro
Date: 16 Sep 2021 19:15:00
Message: <web.6143cf38b21f010ccb705ca46e741498@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>
> > > Aren't the HKL values just the vector normals of the planes?
> > > That's what the wikipedia articles suggested on my brief skim.
> > >
> > > Would not plane {y, 0} have an hkl index of <0,1,0>?
> > >
> > > Not sure what the overall goal is, so not sure what to suggest to test this.
> > >
> > If I remember correctly, that is indeed the case I believe.
> >
> > --
> > Thomas
>
> So then, to some degree, the unit cell for the crystal should be some form of
> intersection between all of the planes that the hkl indices define. (?)

I think the unit cell defines the dimensions and angles. Attached is a
screenshot from KrystalShaper. The thin-lined, skewed box surrounding the
crystal represents the unit cell. In the lower right area of the image you can
see the numbers "4.913 x 4.913 x 5.4045" which are probably the dimensions of
the cell. The numbers "90 90 120" are the angles. But how to convert these to
proper planes? All my attempts have failed. There is probably a basic solution
and I'm just over-complicating things...

> Does the file format include any data that would serve as an offset?

The data files are in some non-human-readable format. I should probably get a
hex editor and take a look.

> Creating the most basic crystal shapes, probably starting with cubic NaCl, might
> give a clue as to how to code an implementation of that notational system.

Yes, I should start with the most basic thing first.

Sam


Post a reply to this message


Attachments:
Download 'krystalshaper-quartz.png' (18 KB)

Preview of image 'krystalshaper-quartz.png'
krystalshaper-quartz.png


 

From: Bald Eagle
Subject: Re: Granite_21 - the final macro
Date: 17 Sep 2021 06:30:00
Message: <web.61446d55b21f010c1f9dae3025979125@news.povray.org>
"Samuel B." <stb### [at] hotmailcom> wrote:
In the lower right area of the image you can
> see the numbers "4.913 x 4.913 x 5.4045" which are probably the dimensions of
> the cell. The numbers "90 90 120" are the angles. But how to convert these to
> proper planes? All my attempts have failed. There is probably a basic solution
> and I'm just over-complicating things...

I agree that those are the dimensions and angles.
But they are the angles of the unit cell, and ATM I fail to see how you need
them.

What I DO see, is that you have numerical triplets, indicating the hkl indices.
I believe that you can simply use those numbers as the normal vectors for all of
the face planes.  Maybe there's a way to display them with greater precision.
Still not sure about the offset, but maybe once you get the ball rolling, some
light will be shed on that aspect of the data.

Perhaps if there are tables of human readable hkl indices for different crystal
structures, you can compare and contrast and discern a pattern.

And that's all I have before 1st coffee.   :D


Post a reply to this message

<<< Previous 8 Messages Goto Latest 10 Messages Next 10 Messages >>>

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.